Question

There is something confusing with the question. look at the given image and try to find the answer.

AB=DC, DC=BC, ADC angle = 40, BCD angle = 140 Find ABC.​

Answer 1

Answer:

BAD+∠BCD=180°  (opposite angles of a cyclic quadrilateral are supplementary).

∴100°+∠BCD=180°∠BCD=80°

(ii) ∠ADC=∠BCD   (Alt angles are equal)

∠ADC=80°

(iii) ∠ABC=∠BAD  (Alt angles are equal)

∠ABC=100°